Pre-Jutland Battleship Design Studies
Before the war, sketches for potential battleships for the 1916 programme had been drawn up, with ten or even twelve 38cm (15in) guns, with both all-twin and a mixture of twin and quadruple gun layouts being considered, the increase in calibre was an insurance against Great Britain increasing calibre beyond eight 15in guns in the Queen Elizabeth and Royal Sovereign classes. Work apparently stopped on these designs before the outbreak of war.

In May 1916, three battleship designs (L 1-3) were put forward in parallel with the GK 1-3 large cruiser series. They were of similar size, but of 25/26kts speed, thicker armour and, in one case (L 2) ten 38cm guns. However, it was not until the postponement of new-construction large cruisers, and the completion of the redesign work for the Ersatz-Yorck class that serious attention was paid to them. Armament options put forward were eight 42cm (16.5in), ten 38cm (15in) and eight 38cm guns, the first two were limited to 22kts, but the third was to be capable of 25kts. They were based on twin turrets, although the General-2 Office argued for the advantages of quadruple turrets (as were already being used on the French Normandie class).

The L 1-3 design series incorporated improvements over the Baden class, they were longer and faster.

Post-Jutland Battleship Design Studies
After the experiences of Jutland a vast discussion with plenty of new ideas and designs started that lasted until the end of the war and some of these studies were far developed and represent possible new designs of a German post-war fleet. Part of the discussion was also the question, if the two types of battlecruisers and battleships should and could be combined into a fast battleship type. This was not an easy question, because the draft and beam of such a ship needed an extension of the harbour-locks in Wilhelmshaven and also of the dry-docks, and just a few floating docks could keep such large ships. Another problem was that the waterways along the coast and embouchures need to be dredged out for them. The 42cm gun (16.5in) projected for those designs were under pre-development by Krupp since late 1916. So it is pretty sure that this calibre would have come after the war.

Four basic 42,000 ton designs were issued toward the end of 1916, L 20 b with eight 42cm (16.5in), L 21 b with ten 38cm and L 22 c with eight 38cm. By August 1917, the eight 42cm option was the preferred one, with schemes L 20 e and L 24 put forward, differing principally in that the latter had an extra 1.5kt in speed, requiring a 3m longer hull and an extra pair of oil-fired boilers (and thus a wider funnel). With further development (and growth), schemes L 20 eɑ and L 24 eɑ, displacing 44,500 ton and 45,000 ton were produced in October and formally submitted in January 1918.

Compared with earlier battleships, the secondary battery was reduced to twelve guns, and L 24 eɑ had an additional pair of torpedo tubes, placed above-water. Armour was broadly on Bayern lines, but with some rearrangement. When considered by the Kaiser, he returned to the recurring theme of the need to rationalise to a single kind of capital ship, together with the impossibility of continuing the continuous increase in size of ships. He therefore directed that a faster vessel should be produced by deleting the forward superimposed turret and the submerged torpedo tubes.

CinC High Seas Fleet subsequently queried whether triple or quadruple turrets might save enough weight to reach 30kts, delaying further design work until the summer of 1918, when the studies indicated that there would be few worthwhile savings, while rate of fire would be negatively impacted. Accordingly, two designs were put forward, one with eight 42cm and a trial speed of 26kts. In the end, on 11 September 1918, it was agreed that L 20 eɑ should be the basis for the next German battleship, to partner a new large cruiser, the desire to replace both with a single 'large combat ship' having been overtaken by practical considerations.

L 20 e and L 24 Battleship Design Study Series
Following the Battle of Jutland on 31 May – 1 June 1916, Admiral Scheer, as commander in chief of the High Seas Fleet, pushed for new and more powerful battleships. He demanded the new ships have guns of 42cm (16.5in) calibre, an armoured belt 350mm (14in) thick, and be capable of speeds of up to 32 knots, all on a displacement of up to 50,000 tons. On 21 August 1917, the construction department submitted two design proposals for the new battleship class, L 20 and L 24. The primary difference was the placement of the ships' torpedo armament. The L 20 design placed them in the hull below the waterline, while the L 24 proposal used above-water launchers. Displacement for the designs was fixed at 45,000 tons.

L 20 e Battleship Design Study

Main Armament
The new 42cm (16.5in) SK L/45 gun was to fire a 1,000-kilogram (2,200lb) shell out to 33,000m (108,000ft) at the maximum elevation of 30 degrees. The estimated muzzle velocity was 800 metres per second (2,600ft/s). They were to be housed in turrets which were arranged in super firing pairs fore and aft, the latter being widely separated by engine rooms. Designed by 29 December 1916, and approved on 11 September 1918, no 42cm (16.5in) SK L/45 guns were built.

Secondary Armament
The secondary battery of twelve 15cm (5.9in) guns was to be mounted in casemates, as was standard for ships of the time. The anti-aircraft battery was to have consisted of either eight 8.8cm (3.45in) FlaK L/45 guns or eight 10.5cm (4.1in) FlaK L/45 guns. The design was to have been equipped with three torpedo tubes, either 60cm (23.6in) or 70cm (27.6in) in diameter. One torpedo tube was placed in the bow, the other two on either beam to the rear of the engine rooms.

The L 20 e project never left the drawing board as on 2 October 1917 the L 20 α proposal was selected instead.

Battlecruiser (Grosskreuzer) Design Studies
On 19 May, in preparation for a meeting between von Capelle and the Kaiser, Department K presented some preliminary designs, or sketches, for both battlecruisers ( designs GK 1, GK 2, and GK 3) and battleships (designs L 1, L 2, and L 3), which were to be used as baselines for future developments. All sketches envisaged a main armament composed of eight 38cm SK L/45 guns, sixteen 15cm guns 8.8cm AA guns. As far as battlecruisers were concernd, the designs envisaged a notable increase in the displacement, intended especially to enhance propulsion power and lengthen the hull to allow greater speed. Protection was subject to only minor changes.

The GK 1 sketch called for a normal displacement of 34,000 tons, a waterline length of 235m and a power output of 110,000shp, with a corresponding speed of 29.25kts. In the GK 2, a 38,000 tons and 243m, engine power increased to 120,000shp and speed to 29.5kts. Machinery layout included twenty-four coal-fired and twelve oil-fired boilers. The GK 3 sketch maintained the same displacement and length as GK 2, but had a power output of 115,000shp and a speed of 29kts; there was more focus on protection, especially horizontal. Both von Capelle and Department K were orientated toward the GK 1 sketch, this being less ‘racy’ than others and more compatible with some constraints, including access to German naval bases. The commander of the Hochseeflotte, Admiral Reinhard Scheer, favoured the GK 3, judging it as the best combination among firepower, speed and armour protection.

The existing disagreements on speed, when this was sacrificed for protection, suggested – together with other issues – further insights. Between May and July 1916, Department K worked out a new design, the GK 6: it had a displacement of 26,500 tons and a length of 235m, the same protection as GK 3, but was also in accordance, if circumstances would allow, with the transition to the single type of ship-of-the-line that Wilhelm II hoped for. Scheer and Department A opposed GK 6. They believed that its speed was insufficient, while protection and main armament did not implement, in their opinion, the lessons learned from Jutland. They suggested installing a fifth 38cm turret or, as an alternative, to switch to 42cm as the main calibre. Meanwhile, the work slowdown and further unavoidable delays postponed delivery to 1920-21 and caused fears that the battlecruisers, once completed, could either be obsolete and/or largely inferior to their British counterparts, as a result of an inappropriate choice of their characteristics and performance.

This design series was a further expansion on the Mackensen/ Ersatz York Classes, slightly enlarged and with a new design 38cm (15in) main gun.

*Grosskreuzer is the German word for Large Cruiser, which was the closest to the English term ‘battlecruiser’ the Imperial Navy was to get.

Large Combat Ship (Grosskampfschiffe) Design Studies
In considering how the lessons of Jutland might affect future design, a key constraint remained the Wilhelmshaven locks, with the III. Entrance’s capacity of 235 x 31 x 9.5m being the principal one: any larger ship would need a new lock, but basin-size and water-depth in the Jade and Elbe rivers were also problematic.

The Navy Office was now keen (as the Emperor had long been) to produce a fast battleship (‘large combat ship’ [ Grosskampfschiffe’]) to supersede both battleships and large cruisers in future programmes, but CinC High Sea Fleet objected, stating that his need was for faster large cruisers (having significantly overestimated British battlecruiser speeds at Jutland), not to mention vessels that could match the firepower of the Renowns and overcome the protection defects revealed by Jutland. The Navy Office pointed out that the CinC’s prerequisites could ultimately add 20,000 ton to the existing Mackensen design, and that a moderately modified scheme GK 6 was probably the best that could be achieved without a new Wilhelmshaven lock.

Such a new lock was approved in October, but it would be six years before it could be completed; thus any new construction of large cruisers would have to be postponed for two years to allow the completion and that of the new lock. It was in this context that the decision to complete the Ersatz Yorks with 38cm guns was taken.

Designs to give form to the ‘large combat ship’ concept were produced during the first months of 1918. They were numbered in a GK-series in which the ‘GK’ now signified ‘Grosskampfschiffe’’, rather than ‘Grosskreuzer’, and whose four-digit number encoded the key features of the design. Thus, the first two digits represented the displacement in thousands of tonnes, the third digit indicated the number of main battery turrets and the fourth was the serial number for that size of ship.

These designs discarded the tripod foremast and light main mast seen in the Bayerns and Mackensens in favour of a pair of tubular masts of the kind introduced in Kronprinz, thus giving two elevated fire control positions, each equipped with a rangefinder, clearly learning the lessons of the war. They also replaced the 8.8cm FlaK with a new 15cm AA mounting, possibly recognising the increasing potency of the air threat.

The designs were all intended to achieve a minimum of 30kts, with various combinations of armament and protection, in most cases still within the dimensions permitted by existing dockyard infrastructure. Two, however, GK 4931 and GK 5031, added a further 40m of length after the approval of the fourth Wilhelmshaven lock.

These studies indicated how far high speed imposed major penalties elsewhere in a ship’s design. The smallest of the schemes, GK 3021 and GK 3022 (seemingly inspired by the British large light cruisers of the courageous class), were already at a displacement regarded pre-war as absolute maximum, and were restricted to four 35cm and four/six 15cm and a main belt of minimal (and very un-German) 100mm or 150mm thickness to accommodate the huge machinery plant needed to achieve their intended speeds. This comprised respectively thirty-two boilers for 140,000shp = 32kts and forty-eight boilers (half above the armour deck, as in one iteration of the US Constellation class battlecruisers) for 200,000shp + 34kts, the space dedicated to boilers reflecting an unwillingness on strategic grounds to move to an all-oil fit.

Another 5,000 tons bought 38cm guns and 300mm armour. With another 5,000 tons to get 42cm guns. A displacement of 45,000 tons allowed an increase in the main battery to six 42cm guns (and 350mm armour), the latter requiring 220,000shp to achieve his 32kts speed. What all this work did was to demonstrate that the combination of high speeds with the kind of armament and armour desired by the High Seas Fleet were impractical in the face of current infrastructure constraints. Accordingly, the last of the series of design-studies were once again designated in the L-series as battleships, L 27 of May 1918 reverting to 45,000 tons and carrying six 42cm guns and a 350mm belt at 29kts. All this contributed to the decision to retain the separate battleship and large cruiser categories for the first post-war capital ship programme, with the decision as to the priority reserved for the Kaiser.

* These designs were not numbered sequentially; the first two digits were the displacement in thousands of tons, the third digit is the number of main turrets and the fourth digit was a series identifier.

GK 4521 Large Combat Ship Design Study

GK 4531 Large Combat Ship Design Study

The GK 4531 had the same specification as the GK 4521 except for having six 42cm guns in a 3 x 2 arrangement.

GK 4532 Large Combat Ship Design Study

GK 4542 Large Combat Ship Design Study

The GK 4542 design study was a 1918 project for a 45,000 ton fast battleship, armed with eight 42cm (16.5in) SK L/45 guns in four twin turrets, in a superfiring arrangement on the centreline. Secondary armament consisted of eight 15cm (5.9in) L/45 guns in casemates, four 15cm (5.9in) L/45 AA guns in turrets and one torpedo tube in the bow. Dimensions was to have been 240m (787.40ft) long, with a beam of 33.5m (109.9ft) and a draught of 10m (32.8ft). His speed was estimated to be 30kts. Armour protection was a 300mm main belt and 350mm turrets.

A variation of the GK 4542. The GK 4541 design study was a 1918 project for a 45,000 ton battlecruiser, armed with eight 42cm (16.5in) SK L/45 guns in four twin turrets, in a superfiring arrangement on the centreline. Secondary armament consisted of eight 15cm (5.9in) L/45 guns in casemates, four 15cm (5.9in) L/45 AA guns in turrets and one torpedo tube in the bow. Dimensions was to have been 240m (787.40ft) long, with a beam of 33.5m (109.9ft) and a draught of 10m (32.8ft). His speed was estimated to be 30.5kts. Armour protection was a 300mm main belt and 350mm turrets.

The L 28 design study was an attempt to combine high speeds, large calibre main guns and thick armour protection in a ship that could be built by Germany’s existing infrastructure, inevitably forcing a reduction in the number of turrets, as well as protection. This contributed to the decision to retain the separate battleship and large cruiser categories for the first post-war capital ship programme.

The L 28 was armed with six 42cm L/45 guns in a 3 x 2 arrangement, weighed 45,000 tons, had a speed of 29 kts and had a main belt 350mm thick.

Speaking of details, I don't think the grey outline for an entire flag is required, just for the white sections.

As someone who knows a bit more about these designs as me, what were the exact differences between the L20α and the L20e and why was the α-Version chosen in the end? Also, I noticed the crest at the bow of the L20e. Is that something you made up or does it represent an actual crest?

_________________My worklist
Any help and source material is always welcome.

Speaking of details, I don't think the grey outline for an entire flag is required, just for the white sections.

As someone who knows a bit more about these designs as me, what were the exact differences between the L20α and the L20e and why was the α-Version chosen in the end? Also, I noticed the crest at the bow of the L20e. Is that something you made up or does it represent an actual crest?

I hadn't thought about that on the flags, i'll update them, thanks.

I own a book, which has a lot of information on this subject and many drawings, which are available on a link i posted on the L20 e Topic; Deutsche Grosskampfschiffe 1915 Bis 1918. Die Entwicklung Der Typenfrage Im Ersten Weltkrieg.

I used Google Translate and this is what I got:

"The Entwurfe L 20 e and L20 eα and L 24 and L24 a differed with only slightly changed dimensions mainly by the torpedo armament, of which the Breitseitrohre were arranged in the original execution under water, at the changed execution over water. The change in TR was therefore carried out in order to win by the cessation of the Breitseitraumes space for another oil boiler room, making a slightly higher rate could be achieved. On 11 September 1918 Kaiser Wilhelm II ordered the construction of the draft By L 20 eα, of all Entwurfen which alone intends its realization."

I know Breitseitrohre and Breitseitraumes are torpedoes or torpedo room etc.

The drawing for the L20 eα (There's no L20 α in the book from what I can see) is pretty much the same as the L20 e, except that the funnel isn't as wide and there's a slight change to the superstructure, inbetween the funnel and the rear director station. Looking at a table of stats I believe the speed?? (Geschw. kn) was 25,0 (23,5) for L20 e and 26,0 (24,5) for L20 eα.

I do wish I could speak and read German, as well as my own language, Welsh. I'll try to translate more when I can.

Further to my last, I had a look on Wikipedia and the German version of the L20 page has L 20 eα whislt the English version has L20α